Comparison of wet combing with malathion for treatment of head lice in the UK: a pragmatic randomised controlled trial

Lancet. 2000 Aug 12;356(9229):540-4. doi: 10.1016/s0140-6736(00)02578-2.


Background: Concern about the effectiveness and toxicity of insecticide lotions has led to promotion of mechanical methods to remove head lice. We compared the effectiveness of "bug-busting" (wet combing with a fine-toothed comb) and malathion lotion.

Methods: We screened 4037 schoolchildren in two counties in Wales, UK (intermediate resistance to malathion). Of 167 found to have head lice, 81 (aged 3-14 years) were eligible to participate in a randomised controlled trial that compared mechanical removal of lice by a commercial kit every 3-4 days for 2 weeks with two applications of 0.5% malathion lotion 7 days apart; parents carried out both treatments. The outcome measure was the presence of live lice 7 days after the end of treatment. Analyses were by intention to treat.

Findings: 74 children completed the study and 72 were included in the analysis. The cure rate was 38% (12 of 32) for bug-busting and 78% (31 of 40) for malathion. Children assigned bug-busting were 2.8 (95% CI 1.5-5.2) times more likely than those assigned malathion to have lice at the end of treatment (p=0.0006).

Interpretation: Malathion lotion was twice as effective as bug-busting, even in an area with intermediate resistance. Policies advocating bug-busting as first-line treatment for head lice in the general population are inappropriate. Assessment of the outcome of treatment 1-2 weeks after completion is essential for successful management. Only about 50% of participants complied fully with treatment, so future trials should be pragmatic in design, avoid false incentives, and study representative samples of children.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Animals
  • Child
  • Child, Preschool
  • Humans
  • Insecticides / therapeutic use*
  • Lice Infestations / drug therapy
  • Lice Infestations / therapy*
  • Malathion / therapeutic use*
  • Pediculus*
  • Scalp Dermatoses / drug therapy
  • Scalp Dermatoses / therapy*


  • Insecticides
  • Malathion